Elastic-fluid turbine.



R. H. RICE.

ELASTIG FLUID TURBINE. APPLIUATION rum 215.10, 1908.

Patented J uly 5, 1910.

Witnesses fpass to atmosphere.

UNITED STATES PATENT OFFICE.

RICHARD H. RICE, OF LYNN, MASSACHUSETTS, .SSIGNOR TO GENERAL ELECTRICCOMYANY, A CORPORATION 0F NEW YORK.

ELASTIC-I'LUID TURBINE.

Application tiled February 10, 190B.

To all whom it may concern:

Be it known that I. Ricimnn H. Rica. a citizen ot' the United States,residing at Lynn, county of Essex, State of Massachusetts, have inventedcertain new and useful Improvements in Elastic-Fluid Turbines, of whichthe following is a specitication.

The present invention relates to elastic fluid turbines. and moreespecially to those of the impact type, and has for its objects toimprove their etlicieiiey and also their construction. In theaccompanying drawing which illustrates one of the embodiments of myinvention, Figure l is a partial axial section of a vertical shaftturbine; Fig. 2 isa detail sectional view taken on line 2-2 of Fig. l;and F ig. 3 is a view in side elevation of a turbogenerator.

1 indicates the base. ot' the turbine havin-r an outlet 2 through whichthe exhaust .steam normally passes to a condenser or it, may Bolted tothe base is a spider 3 that. supports the stepand lower guide bearings.and carried by the base. is a parl-:ing 4 to prevent the escape ot'steam from the chainbered base; or the entrance of air.

5 indicate the niaiii shaft upon which awy I n been pointed out. thevelocity of the tluid secured the bucket wheels, a single whwi with tworowsl ot bueliets being provided for each stage.

Mounted on the base is a wheel casing made up in segmental sections ofsuitable size. the upper or high pressure end of the easing being largerin diameter than the bottom or low pressure end The upper end of theeasing is provided with a head 't' having a central bore through whichthe shaft passes and a par-king 8 to prevent the escape of steam orother elastit-.lmotive fluid. In the head are passages l) communicatingwith the val\e chest l() and with the sections or pai-'sages of thedivergent nozzle 11 bolted or otherwise secured to the under side of thehead. These admission nozzles cover a relatively small wheel are andhave a 'greater iatio of expansion than the stage nozzles so as toreduce the pressure within the first stage or wheel compartment to sucha low value under all conditions of operation as to keep the strains onthe casing within a safe margin.

The idea of a multistage impact'. type of turbine operating with agreater pressure Spee? cation of Letters Patent.

Above the guide -bearing Patented Juiy 5, 1910.

Serial No. 415,024.

drop in the first. than in any one of the subsequent stages is notofitself broadly new but I provide for a materially greater ressure dropthan has been contemplated 1eretofore, and by reason of this and otherfeatures am enabled to obtain superior results. Turbines of thecharacter referred to are provided with stage nozzles which are normallyin service and other stage nozzles which are putJ into serviceautomatically or otherwise as the, load increases and` the steampressure in the, first stage tends to build upor when additional steam-is needed. Then the stage valves operate automatically they are.arranged, in so far as possible, to maintain a constant stage pressureunder varying conditions of load. By reducing the pressure in the firststage to an extremely loir7 value as I do, it is lower at', light loadsthan is necessary to safeguard the wheel casing, hence when the load in;creases to maximum the pressure will only rise by a certainpredetermined amount, the total value of which does not exceed the safeworking limits of the casing and its parts.

liroin this itwill be understood that I ain' able to dispense with stagevalves, and hence all of the stage nozzles will constantly be iu servicewhen the turbine is in use. As has ATssiing from the admission nozzlesis greater `han that from the stage nozzles7 hence in order to extractan amount of velocit from the steam in the first stage comparab e withthatI extracted .in the subsequent stages the bucket speed should behigher. This is attained by making the first stage 'wheel larger indiameter than the wheels of the subsequent stages. Oiving to the factthat the pressure in the tirst stage is abnormally low as conti-:Medwith pressures previously eniployed, l' ain able. to utilize a wheel oflarge diameter and this withoir` high rotation losses because ot' thelow density of the steam. By rotation losses .I mean the losses due tofriction between the wheel and the surrounding medium and the fan-likeaction of the wheel buckets. Decreasing the first stage pressure asdescribed renders it easier to pack the wheel shaft. where it passesthrough the easing head. Other things being equal it also reduces theweight, of the casing, head, diaphragm, etc. Dispensing with stagevalves reduces mechanical complication and initial cost. Further itdecreases the number of parts which have to be looked after by theengineer in charge of the machine.

As above stated, in my improved turbine the velocity ot' the steam inthe first stage is higher than in any ot the remainder` and the saidstage does considerably more Work, in

the turbine illustrated about one-third of the .creases without,however, endangering the casing, and lsince the pressure distribution inthe stages changes somewhat under these conditions the lower pressurestages will automatically do more work as the pressure increases. As theload falls ottl the pressures in the several stages gradually changeuntil the initial condition is resumed. As an eX- ample of the pressurerelations: that of the supply may be 200 pounds absolute, the pressurein the first stage 30 pounds absolute, and that of the exhaust l poundabsolute. The great drop in pressure due to the nozzle 1l havingdivergent walls results in a high spouting velocity of the steam. Inorder to etfectually utilize this velocity I provide a bucket wheel l2in the first stage of considerably larger diameter than those of thesucceeding stages, and owing to this large diameter the bucket speedclosely approaches the theoretical for the conditions mentioned. Forexample, the bucket speed may be 500 feet per second with a normalspouting velocity at the nozzle end of 2200 feet Der second. Thediameter of the upper end of the casing is greater than that of thelower end` to accommodate the large bucket wheel. At the point of changein diameters a shoulder is provided upon which rests the largestdiaphragm 13 in the machine. lt is not only larger in diameter but it isalso thicker. Surrounding the diaphragm is an annular chamber 14. theannular outer and bottom walls beingr formed by the casing. the innerwall by the l'tcriphery ot' thc diaphragm and the upper wall by arclativck,Y thin metal ring 15 riveted or otherwise attached to aninternal projection on thc wheel casing and to the peripheral edge ofthe diaphragm. This ring is cnt away at a pointdirectly under theadmission nozzles to t'orm a segmental opening ol suitable .shape andarea to permit the steam exhausting from the whccl-t0 freely enter it.it is to be noted that the annular chamber ll surrounds thc diaphragm13B instead ol" bcing conlncd in a .small arc directly between thcexhaust side ol' thc lirsl uio-cl and l-lnI nozzles ol. the nc.\t stage.This arrangement. permits olI a chamber of large cross-section withoutincreasing the, axial length of the turbine by any appreciable amount.Owing to the great drop in pressure in the admission nozzles the volumeof the steam increases enormously by the time it enters the chamber andto utilize this to its best advantage all of the stage nozzles leadinginto the second stage as well as those leading into the succeedingstages are active. Boiled to the largest diaphragm is a stage nozzlel 16that imparts velocity to the steam and completely surrounds the secondstage wheel so that all or practically all oi: the buckets will beactive. This nozzle or the sections thereof are fed with steam from theannular chamber 14 by passages 17 cored in theperipheral portion of thediaphragm. Owing to the fact that the chamber 14 is annular andcommunicates with all of the second stage nozzles the latter are allsupplied with steam at the same pressure.

The stage nozzles may be divergent or nondivergent in character, in anyevent the velocit of the motive fiuid discharged thereby will econsiderably less than that discharged from the admission nozzles. Forexample, the spouting'velocity of the steam atthe ends of these nozzlesmay be 1G00 feet per second when that of the adniission nozzle is 2200feetl per second. Under these condi-A tions the bucket speed of the lowpressure stages can with advantage be about 425 feet per second.

' In the second stage compartment 18 is a bucket wheel 19 ofconsiderably smaller diameter than the one in the rst stage. This wheelas well as the others in the turbine are each provided with two rows ofbuckets Q0 and intermediate buckets ,21 between the rows. In the firststage these intermediates cover only a comparatively small wheel arc,substantially the same as covered by the admission nozzles, while in thesecond and in the succeeding stages they cover the entire wheelcircumference. I

The diaphragms between the stages of the lower pressure diti'er inconstruction from thc large high pressure diaphragm. Since theconstruction of these diaphragms and their supports are the same adescription of one ot them will be sulticient.

Formed on the inner wall of the wheell casing is a shoulder 22 andseated thereon is a ring comprisingan inner and an outer cast metalportion and sheet metal partitions dividing thc space between them intopassages all of which extend in the .same direction and discharge .steamal the same angle to tho wheel buckets. ln .':iaking these rings theshcct metal partitions are put into the coreI and the coro is thenplaced in the mold in the, usual manner. The part of the mold formingthe inner portion of the ring is poured lit-sl. 'tcr thc metal has had aizo chance to cool somewhat the outer portion of the ring is poured. Incoohng the outer portion will contract somewhat and instead .of thepartitions being under tension, as

. which I regard as being an important adwould be the case if the partswere poured simultaneously, they are under compresslon vantage. In sofar as the broader features of my invention are concerned they are notto be construed as limited to the particular construction of these ringsand diaphragms. The outer portion ofthe ring rests on the internalshoulder of the casing While its inner portion is provided with ashoulder to receive the diaphragm prcper. This diaphragm 24 is providedWith a shaft opening and supports a packing sleeve 25 of suitablecharacter around the shaft.- It is provided With concentric ribs tostrengthen it, and also with sheet metal disks 26 on opposite sides eachof which present a smooth surface to the steam in the compartment soasnot to oppose its movement, and also to decrease the size of the Wheelcompartment so as to limit the amount of steam contained therein.Located above the casing is a stool 27 that supports the casing 28 of anelectric generator. The upper end of the turbine shaft is provided witha guide bearing .29 supported y the stool. On the end of the shaft is acoupling 30 for uniting it with the generator shaft 31 above it. Theguide bearing is supported at suitable points by the stool and betweenthe points of support are spaces to erxnit of access to the bearing.From this it follows that the heated air from around the turbine wouldpass directly into and through the generator thereby increasing itstemperature and endangering its life. To prevent this a ring shapedplate 3; is provided that is bolted to the stool or other supporte It isprovided with one or more openings through which access may be had tothe parts above. and these openings are covered by doo 's that are heldin placeA by bolts or other means.

By reason of my im proved construction I am able to produce a turbinewhich has a relatively low shaft speed and at the same time one havinghigh economy of operation. The parts are simple and rugged inlconstruction and the machine can be erected or taken down with aminimum expenditure of time and labor. By using a larger first stagewheel and a' casing having two diameters. ample provision can be madefor the annular chamber receiving steam therefrom and this Withoutunduly increasing the axial length of the machine. Since I avoid the useof stage valves and separate nozzles controlled thereby 'the first costof the machine is materially reduced as is also the number of parts. Thecost. of attendance and main tenance is also reduced.

I have shown the Wheels all located in the same casing since this is adesirable construction but the. invention is not to be construed as solimited unless specified in the claims.

I obtain the high bucket speed of the first stage by `using ay largerwheel than in the later stages and mounting all of the wheels on thesame shaft, but in those cases vvhere a divided shaft arrangement can beutilized IVhat I claim as new and desire to secure by Letters Patent ofthe United States, is.-

l. A turbine that is divided into stages of expansion, divergentadmission nozzle which discharges the motive fluid into the first stageat a pressure that is only a small perccntage of the initial pressurewith a correspondingly high velocity so that a larger l percentage ofthe Work will be performed in the first stagethan in any one of thelater stages and the casing strains under varying load conditions andthe leakage losses will be reduced -to a relatively low value, a wheelfor said stage that has a bucket speed great enough to effectivelyconvert the high vc locity ot the fluid into mechanical work. stagenozzles each of which converts a lesser percentage of the pressure intovelocity than the said admission nozzle. a wheel for cach of thelo\.\.'pressure stages located adjacent its nozzle v.bich acts on theimpact plan to fractionally extract the velocity, each wheel having aucket speed which is less than that of the initial stage, shaft meansfor carrying the wheels, inclosing means. for the wheels, andexhaust-receiving means.

2. In combination, a turbine divided into stages, admission and stagenozzles, the former having a greater ratio of expansion and imparting agreater velocity to the motive fluid than the latter. bucket wheels forthe stages all of ivhich act on the impulse plan to extract the'velocitvproduced b v the nozzles in successive operations, one of the highpressure. stage Wheels operating at a higher bucket speed and performinga greater amount of Work than a low pressure stage bucket wheel, and anexhaust conduit.

3. In a multi-stage turbine, the combination of a casing. means dividingthe turbine into separate wheel compa rtmcnt;'- or stages. a supplychest, admission and stage nozzles, the former shaped to cause a greaterdrop in pressure and a. higher spouting velocity of the. motive fluidthan the latter, bucket wheels in the. stages, the bucket wheel in the,first stage havin" a. greater diana-ter than the remaining w ieels andperforming more work than said wheels, and an exhaust conduit.

4. ln combination, a turbine divided into st ages, admission nozzleswhich cover a limited wheel arc and cause a greater drop in pressurebetween the source of supply and the tirst stage than do all of thestage noz- '/.lcs combined, stage nozzles, a bucket wheel for the tirststage acting on the impulse.

plan, the buckets ot which have a greater velocity than those ot' thesubsequent stages, bucket wheels for the remaining stages also acting onthe impulse plan to extract the velocity of the motive Huid' insuccessive operations, and an exhaust conduit.

5. In combination, a turbine divided by diaphragms into stages, anadmission nozzle which imparts a greater velocity to the motive fluidthan do the stage nozzles, a bucket wheel cooperating therewith whosediametervis greater than that of the wheel of the stage of lowestpressure and which performs more work, an annular chamber which receivesthe fluid exhausting from the first stage and supplies it to the next,stage nozzles converting the pressure of the fluid into .\'elocit v,certain ot' said nozzles receiving motive fluid from said chamber,rotating buckets for the remaining stages all of which act on theimpulse plan, and an exhaust conduit.

(i. In a turbine, the 'combination of a shouldered easing, a supplyconduit, a removable diaphragm resting on one of said shoulders andwhich divides the easing into compartments. an aiiiinlar chamber whichis located between the periphery ot' the diaphagn'i -and the inner wallof the casing,

wheel buckets exliaustiif;- into the chamber.

stage nozzles receiving motive fluid from the chamber, the conduits inthe peripheral face of the diaphragm supplying motive fluid to saidstage nozzles. additional dia-Y phragins resting on shoulders in theeasing for dividing the latter into other compartments, stage nozzlesland rotating buckets for the last mentioned compartments, and an exhaustronduit.

i. ln a turbine. the combination of a casing havingr portions oldilferent diameter with :i shoulder between the one of larger diameterbeing located at the high pressure are supported b v theportionthereot'liaving the smullendiameter, an aimular chamber boundedby the tirst mentioned diaphragm. the shoulder und llic lniu-r wall olthe cas ing, rotating buckets for the compartments separated by thediaphragms, admission and stage devices discharging Huid to the buckets.and an exhaust carrying means.

S. Tn a turbine, the combination of a easing liai'inga high pressureportion ofgreater diameter than the low pressure portion with a shoulderbetween, a diaphragm which rests on the shoulder. divides the casinginto compartments and is provided with passages communicating with thetiuid discharging devices of the adjacent stage, an annular chamberwhich surrounds the diaphragm and supplies tluid to the passages, meansdividing the casing into additional compartments, admission and stagede"ices for discharging motive fluid, buckets for the compartments forextracting energy from the motive tluid, and an exhaust conveying means.

il. ln an elastic fluid turbine. the combination of a casing. meansdividing it into stages or compartments, rotating buckets for the stageswhich abstract velocity from the motive fluid due tothe nozzles, thosein the' tirst stage performing a greater amount of work than those inany other stage, a support 'for the buckets, the portion for the highpressure stage buckets heilig greater in diair eter than the remainderto give a hit?l 1' bucket. speed, admission nozzles which impart to thetliiid a greater velocity aecoinpined by a greater pressure di'op thando the stage nozzles, the said admission nozzles supplying fluid to onlya limited number of buckets, stage nozzles which imi-irtvelocity to thefluid and discharge itt-i il of the buckets in the. remaining stages;and an exhaust conveying means.

lt). ln au elastii` fluid turbine, the combination ot' a shouli eredcasing, a diaphragm which rests on the .shoulder and divides the casingi'nlo compartments. :in aunula'r nozzle ou the low pressure side ot thediaphragm, and passages in the diaphragm which open on the peripheralt'ace thereof and convey fluid to the nozzle ou the side thereof.

11. ln a turbine, the combination of a casing, wheel buckets therein, avertical shaft carrying the buckets, a device driven by the shaft.bearings for said shaft,I a means for preventing fluid at. hightemperature from aroiiud the turbine passingupward into the said device,a door in said means through which access may be had to the parts ofsaid device, and means t'or conreyingmotive fluid to and from theturbine.

ln witnesswliereol, l have hereunto set ltltllXltl) ll. RICE.

